The present invention relates to a cooling system and electronic apparatus in which ambient temperature of a data center containing therein the electronic apparatus is adjusted.
An electronic apparatus such as a disk array apparatus is configured by being loaded with a number of magnetic or optical disk drives inside a casing to enhance reliability of data storage. These disk array apparatuses are operated by management software by being connected with a high-speed special network line such as an optical line, and used as a SAN (Storage Area Network), NAS (Network Attached Storage), or a single RAID (Redundant Array of Inexpensive Disks) disk apparatus.
The main heat generation sources of the disk drives loaded on these disk array apparatuses are control electronic components such as a drive motor, an actuator, and an LSI. Heat of them is cooled by cooling air which is supplied by the cooling fan installed in the disk array casing. When the cooling ability is low, the temperature of the disk drives rises, which results in an error operation and degradation of long-term reliability. Further, heat generation of the controller which controls exchange of data between an external controller and disk drives is likely to be large.
When cooling ability is insufficient, the temperature of these controllers rises, and as a result, an error operation and occurrence of element breakdown are feared. Further, reduction in noise which occurs from the fan for driving the air flow in the disk array apparatus is an important problem, and the air flow quantity required for cooling sometimes cannot be sufficiently secured due to noise.
Thus, the disk array apparatus has the problem of favorable cooling of each of the heat generating members and reduction in noise of the apparatus. This similarly applies to the other electronic apparatuses having heat generating elements such as CPUs.
Due to increase in the scales of storages following proliferation of blade servers and rapid increase in data volume, rapid increase in power consumption becomes a critical requirement for operation of data centers.
A data center is a generic name of the facility which keeps the servers of customers, and provides connection line to the Internet, maintenance and operation service and the like. In the data center, a number of severs and storages are installed in rows, and air conditioning equipment which cools them, an uninterruptible power supply prepared for power failure, a private power generator and the like are included.
The heat generation amount of a server increases at an annual rate of 20 to 25%, and it is estimated to be about 20 kW per one casing several years later. Therefore, the ratio of the server power consumption and the power consumption required for cooling it is considered to be 1:1.5 to 2.0 from 1:1 of the present state, and the power required for cooling become a bottle neck.
In the conventional data center and the like, a number of disk array apparatuses and electronic apparatuses are installed in the same space, and as the configuration of the air conditioner, there is generally adopted such a configuration as cold air is supplied from the undersurface side of the floor, and heat is exhausted from the ceiling portion. Further, many of the disk array apparatuses and electronic apparatuses installed in the data centers are mounted in a 19-inch standard rack (the horizontal interval of the screws of the apparatus mounting support post is set as 19 inches, and the apparatus with a width of about 483 mm can be mounted) which is specified by Electronic Industry Association of the U.S.A (EIA) and Japanese Industrial Standard (JIS). In this case, the air for cooling is taken in from the front side of the rack, and exhausted from the rear side.
In the configuration of such an air conditioner, when the disk array apparatuses and electronic apparatuses are mounted with high density, there arises the problem of easily taking in the warmed air in the vicinity of the ceiling again. This is because when circulation of the air inside the chamber is insufficient, the flow easily occurs, in which the warm air rising to the area in the vicinity of the ceiling goes to the front side of the apparatuses in each of the rows of the columns of the apparatus racks. Alternatively, this is because when there are a plurality of rows for the racks, exhaust air of the lower stage of the front side is easily taken into the upper stage of the rear row. This becomes the cause of increase in air conditioning cost and limitation of the number of apparatuses which are mounted.
As the conventional art concerning the data center, the system which monitors the air flow to make cooling efficient, and controls cooling in the data center in accordance with the detected air flow is open to the public (see JP-A-2006-208000). Further, there is provided the system for determining the recirculation index value of air flow (see JP-A-2007-505285).
As the prior art relating to the conventional electronic apparatus, there is the one that supplies cold air from below the floor level of a rack to cooling the apparatuses in the rack favorably, and exhausts warm air from a side of a ceiling (see JP-A-2004-55883). Further, there is the one that identifies a high heat generation apparatus part in the rack, and supplies cold air to it (see JP-A-2001-272091). Alternatively, there is the one that performs heat exchange of the inside of an electronic component storing box by using external air (see JP-A-2001-156478). Further, there is the one that takes in mixture air with external air (see JP-B2-58-16638).